AIDS patients in South Africa are being robbed of their life-saving drugs so that they can be mixed with marijuana and smoked, authorities and health experts say.

The concoction is called "whoonga" - less a word than an exclamation - and it adds a bizarre twist to the war on AIDS in the world's worst-affected country just as it embarks on an enormous distribution of medications.

Whoonga's spread is so far limited to eastern KwaZulu-Natal, South Africa's most AIDS-stricken province, but AIDS and addiction specialists worry that it could reach other parts of the country.

There's no evidence that any ingredient of the AIDS drug cocktail is addictive or does anything to enhance the marijuana high. Whoonga smokers may be fooling themselves into believing the AIDS drugs are giving them a high, when it's really some other ingredient, says Dr. Njabulo Mabaso, an AIDS expert.

AIDS is already a source of damaging myths in South Africa, such as that the disease can be prevented by sleeping with a virgin or showering after sex with an HIV-positive partner.

Some drug dealers are suspected of stretching the whoonga mixture with soap powder and even rat poison to increase their profits.

"We are seeing the use of whoonga in communities and it's very widespread. It's a substance that is openly spoken about in communities," says Lihle Dlamini of the Treatment Action Campaign, which has lobbied hard to improve the government's response to AIDS.

Drug dealers "are taking this treatment that is supposed to assist people living with HIV and abusing it," she says.

In the eastern port city of Durban, Thamsanqa Langa said he didn't know what whoonga was when dealers first started offering the cream-colored powder at 20 rand (about $3) a smoke.

It smelled to him of vinegar, said Langa, a soft-spoken 30-year-old of few words.

At first it just quieted him more. "You feel like you can say nothing. You can just sit in a quiet place, not talking."

But after a few days, Langa said, he started having powerful headaches, stomach pains and night sweats. When he went back to dealers, "They said, 'You need to smoke more, keep on smoking,' " Langa recalled in an interview. "That's how I got hooked."

He mooched AIDS drugs from HIV-infected friends, robbed houses, became a dealer and missed so many workdays that he lost his factory job. He says he smoked whoonga for four years until he gave it up in March.

Vincent Ndunge, a police spokesman in KwaZulu-Natal, said whoonga was first noticed two or three years ago when officers found gangs were robbing people of medication as they left hospitals.

Initially, users crushed the pills and smoked them straight, but added other substances later, Ndunge said.

Carol du Toit of South Africa's National Council on Alcoholism and Drug Dependence, a private organization, also says patients are being mugged for their medications or selling them, and that AIDS clinics are being robbed. She says staff of her private organization are seeing increasing numbers of whoonga users, many of whom also test positive for heroin.

She reports anecdotal evidence of whoonga use spreading beyond KwaZulu-Natal, the country's most welfare-dependent province. But police in Gauteng, South Africa's most populous province and home to the country's economic hub of Johannesburg, say they have not come across the drug.

Foreign experts say they have not heard of such abuse outside South Africa, and are unaware of research into whether AIDS drugs can add anything to a marijuana high. Patrick Abok, a medical officer specializing in HIV for the World Health Organization's South Africa office, said the U.N. agency had no information on whoonga, and referred questions to South African groups.